I'm sorry for asking this again, but is there any new technology in the way of portable battery packs? what do you all recommend? I'm tired of getting burned, (literally), from EBay LiPo packs, it seems they are all garbage. I have been looking at LifePO4 packs but they are so expensive. Any recommendations? I only want to run a 8 to 10 watt LNR Precision FX-4A for as long as possible at 11-12 volts with as little weight as possible, (I know the same thing everybody wants).

I now use 18650 cells. I bought three-cell holders wired in series, which give me 12.6V max, more like 12V after the cells have been off the charger for a bit.

I lost a bunch of LIPO 3S packs because I let their voltage go too low, below 3V per cell. The 18650 might be a little more resilient, but I don't let them go below 3V. I am now very careful about cell minimum voltage and I haven't lost one yet. If you lose a cell you don't lose a whole pack...

I got a bunch of free cells out of old laptop batteries. Usually, they contain six 18650 cells. Even if the battery is bad there are probably only one or two bad cells in it. Ask around, lots of people keep them, along with their old laptops.

For me, 18650s are more economical and practical for the reasons mentioned above.

Hi Joel. For charging I got two Nitecore UM10 USB chargers. I can plug both into my 14W solar panel. Nitecore and Xtar also make 2-cell chargers. I plan on getting one so I can charge three cells at once.

I took my first Gateway Laptop battery pack apart and found 2 bad cells out of 6. The other 4 have 3.7 to 3.8 volts on them. I'm charging them one at a time in a cheapo Chinese 16850 charger for my LED torch. I will look at the charger you suggested and read up on the 16850 chemistry to see how to properly charge them. I know multiple battery packs need to use some kind of load leveling circuit, so I will investigate that as well. Thanks a lot for the tip.

So I bought a Imax B6, (not the fake one). After calibrating it so the voltage reading agrees with my accurate multi meter, I find that it will only charge a single 18650 cell to 4.1 volts or slightly less. I know 4.2 volts is the upper limit, so should it be going higher or is simply being safe. Is that normal? Also the old laptop batteries that I'm using all show that they only are rated at about 1000mah, I thought these were 2200mah batteries. maybe they are just going bad as they are pretty old. I am finding there is a lot to this LiIo charging, but I am determined to build me some portable battery packs. I ordered some balancing cables for the Imax 6 so I can balance charge my packs. Still learning.

4.1V seems ok. As soon as you take the cells out of the charger they will drop to 4V within an hour anyway. Their nominal charge is 3.7V, but they are usually charged to 4.2V. That is the maximum. The 1000mAh you get is a bit low, though it is normal that you get less than the rated capacity since you never discharge them below 3V, otherwise you risk destroying them. When I charge three 18650 cells, place them in a holder and don't use them for a few days the voltage drops to about 11.5V, and that is normal. I still get a lot of operating time from three cells, even with my KX2 drawing 150mA. Using the MTR I never seem to be able to discharge them (35mA)! Used laptop batteries are everywhere. They should all have removable cells, but instead, millions of good cells are thrown away because one or two went bad in the pack, what a waste.

I have noticed the same thing as you, that the cells when they come off the charger are right at 4.1 volts then they slowly drop to about 4 volts, so I'm glad that is normal. I have a Chinese Constant Current Load, (N8Q2), that I checked the same battery on by discharging it to 3V, and it showed the battery at 1750Mah which seems closer to normal than the Imax. Maybe I'm not setting the Imax up correctly. I'm having it discharge at 500ma and have it set for a 1S battery, I'm not sure what else to do. Still learning, and wished I hadn't recycled all those laptop batteries over the years. I'm a computer tech:-( 73

Youkits (a Chinese manufacturer of decent QRP radios) used to sell a 3-cell 12v lipo battery pack to fit some of their CW transceivers and also run their rather nice little antenna analyzers. Unfortunately the carriage services eventually put a stop to their selling the battery packs. I know because I tried to buy three packs myself. They reached Australia but were sent back to Shanghai and I believe Youkits was fined. So they do not sell the battery packs anymore.

Why do I tell you this? Because the cells inside were exactly as described previously. Three 3.7v 18650 cells with a small voltage-balancing circuit board soldered on and neatly shrink-wrapped. The package could be charged by any 12.5 to 13.X charger, and would not overcharge.

So now I have bought some of the 3S cell-holders from off eBay, and bought 3x Youkits (a Chinese manufacturer of decent QRP radios) used to sell a 3-cell 12v lipo battery pack to fit some of their CW transceivers and also run their rather nice little antenna analyzers. Unfortunately the carriage services eventually put a stop to their selling the battery packs. I know because I tried to buy three packs myself. They reached Australia but were sent back to Shanghai and I believe Youkits was fined. So they do not sell the battery packs anymore.

Why do I tell you this? Because the cells inside were exactly as described previously. Three 3.7v cells with a small voltage-balancing circuit board soldered on and neatly shrink-wrapped. The package could be charged by any 12.5 to 13.X charger, and would not overcharge.

So now I have bought some of the 18650 3-cell-holders from off eBay, and bought three 18650 lipo cells locally. (A rip-off from Jaycar Electronics at A$15 each.) But at least I will have another useful way of running a QRP radio in the field. I also bought a NITECORE D4 Digicharger which will run off 12v DC or AC mains (110-240V), and charges up to 4 cells at one time.

I am tinkering with the idea to make a battery pack for outside for quite some time now. First I saw Julians approach with the headway batteries. I discarded that idea because its blowing my budget for the pack. I then researched all possible shops for batteries. In the end, DIY packs with more than 3.5Ah are in my opinion too expensive.How about the idea to buy a battery pack that's already put together? Instead of buying a charger that balances the pack, just upgrade the bought pack with a BMS unit for 10-15$. So you can actually charge the pack via Solar power using a solar charger?